Avalanche Forecast

Issued: Apr 3rd, 2015 9:38AM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Persistent Slabs and Storm Slabs.

bcorrigan, Avalanche Canada

South Coast.

Caution should be used when venturing into big terrain. Buried weak layers are still capable of producing large destructive avalanches.

Summary

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

Around 5 cm of snow is expected this afternoon through to Saturday morning. Then things start to dry out with a mix of sun and cloud on Sunday. Daytime warming will push the freezing level to around 1600 m for the forecast period. Moderate southwesterly alpine winds are expected on Friday then light but gusty south-westerlies for Saturday before shifting to south-easterlies on Sunday

Avalanche Summary

Reported Thursday were several size 2 to 2.5 natural avalanches in steep high alpine terrain, attributed to wind loading. Cornice failures have also been reported recently, triggering large avalanches. We are also hearing of sluffs in steep solar affected alpine terrain.

Snowpack Summary

20-30 cm of low density storm snow is sitting on a strong and supportive rain crust that was buried last Saturday and extends as high as 2100m. West through southwesterly winds have shifted these new accumulations into touchy wind slabs in exposed lee terrain. A facet/crust persistent weakness that was buried in mid-March is now approximately 50-100 cm down. In recent snowpack tests, it was found down 55 cm near the Duffey Lake Road and produced moderate sudden results. This remains the chief concern amongst avalanche professionals in the region because of it's potential for very large avalanches.

Problems

Persistent Slabs

A facet-crust combination from early March is now buried between 50 to 100 cm down. This persistent weak layer is the prime concern right now. Recent storm snow has been redistributed onto lee slopes and may present a hazard as wind slabs.

Be aware of the potential for large, deep avalanches.>Be aware of thin areas that may propogate to deeper instabilites.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Storm Slabs

This storm slab should be bonding well with moderate temperatures and may not present a problem much longer.

Use ridges or ribs to avoid pockets of wind loaded snow.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 4th, 2015 2:00PM